linux-kernel - [PATCH 8/9] eeepc-laptop: check proper return values in get

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Date:	Wed, 17 Sep 2014 23:47:26 +0200
From:	Frans Klaver <fransklaver@...il.com>
To:	Darren Hart <dvhart@...radead.org>
Cc:	Frans Klaver <fransklaver@...il.com>,
	Corentin Chary <corentin.chary@...il.com>,
	Rafael Wysocki <rafael.j.wysocki@...el.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	acpi4asus-user@...ts.sourceforge.net,
	platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 8/9] eeepc-laptop: check proper return values in get_cpufv

In get_cpufv the return value of get_acpi is stored in the cpufv struct.
Right before this value is checked for errors, it is and'ed with 0xff.
This means c->cur can never be less than zero. Besides that, the actual
error value is ignored.

c->num is also and'ed with 0xff, which means we can ignore values below
zero.

Check the result of get_acpi() right away. While at it, propagate the
error if we got one.

Signed-off-by: Frans Klaver <fransklaver@...il.com>
---
 drivers/platform/x86/eeepc-laptop.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/platform/x86/eeepc-laptop.c b/drivers/platform/x86/eeepc-laptop.c
index e93a54e..875a43f 100644
--- a/drivers/platform/x86/eeepc-laptop.c
+++ b/drivers/platform/x86/eeepc-laptop.c
@@ -332,9 +332,12 @@ struct eeepc_cpufv {
 static int get_cpufv(struct eeepc_laptop *eeepc, struct eeepc_cpufv *c)
 {
 	c->cur = get_acpi(eeepc, CM_ASL_CPUFV);
+	if (c->cur < 0)
+		return -ENODEV;
+
 	c->num = (c->cur >> 8) & 0xff;
 	c->cur &= 0xff;
-	if (c->cur < 0 || c->num <= 0 || c->num > 12)
+	if (c->num == 0 || c->num > 12)
 		return -ENODEV;
 	return 0;
 }
-- 
2.1.0

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